Systems and methods for receiving and/or analyzing information associated with electro-magnetic radiation

ABSTRACT

According to an exemplary embodiment, a system can be provided which can have at least one fiber arrangement and at least one receiving arrangement. The fiber arrangement may have optical transmitting characteristics, and may be configured to transmit there through at least one electromagnetic radiation and forward the at least one electromagnetic radiation to at least one sample. At least one portion of the fiber arrangement may be composed of or can include therein sapphire, diamond, clear graphite, Chalcogenide, borosilicate, zirconium fluoride, silver halide, a liquid core light guide, a gas core light guide, a hollow core waveguide, and/or a solid core photonic crystal fiber. The receiving arrangement may be configured to receive the electromagnetic radiation that is filtered and received from the sample. According to another exemplary embodiment, a method can be provided for obtaining information associated with the sample. For example, at least one first electromagnetic radiation can be forwarded to the sample via at least one optical fiber. At least one first characteristic of at least one portion of the optical fiber can be controlled so as to modify at least one second characteristic of at least one second electromagnetic radiation generated within the optical fiber. The second electromagnetic radiation can be associated with the first electromagnetic radiation.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is based upon and claims the benefit of priority fromU.S. Patent Application Ser. No. 60/835,004, filed Aug. 1, 2006, U.S.Patent Application Ser. No. 60/838,472, filed Aug. 16, 2006, U.S. PatentApplication Ser. No. 60/838,285, filed Aug. 16, 2006, and U.S. PatentApplication Ser. No. 60/841,620, filed Aug. 30, 2006, the entiredisclosures of which are incorporated herein by reference.

FIELD OF THE INVENTION

Exemplary embodiments of the present invention relates to systems andmethods for receiving and/or analyzing information associated withelectromagnetic radiation, and more particularly to such systems andmethods which can received and/or analyze such information based onsignals propagated via at least one fiber arrangement.

BACKGROUND INFORMATION

Raman scattering is known to be a vibrational photo-molecularinteraction that provides detailed quantitative analysis of anilluminated sample by examining the light emerging with a wavelength(energy or frequency) different from that of the excitation. In aconventional configuration, a narrow-band light (generally from a lasersource) incident upon the sample of interest is inelastically scattered,and the remitted light is collected (through appropriate optics andfilters) and spectroscopically analyzed.

Raman spectroscopy is a sensitive and specific analytical procedure fordiagnosing various diseases, including atherosclerosis and cancers andpre-cancers of various organs such as brain, breast, colon, bladder,prostate, and cervix, as described in E. B. Hanlon et al., “Prospectsfor In Vivo Raman Spectroscopy,” Physics in Medicine and Biology, Vol.45(2), p. R1 (2000); and A. Mahadevan-Jansen et al., “Raman Spectroscopyfor the Detection of Cancers and Precancers,” Journal of BiomedicalOptics, Vol. 1(1), p. 31 (1996). However, in a number of cases,practical application has been limited due to certain significantlimitations. These limitations include a spectral examination throughoptical fiber probes with diameters small enough to access remotetissues and organs, and competing optical signals from the sample ofinterest, both of which are related to background luminescence andcontribute excessive amounts of noise to the signal of interest.

Catheters and endoscopes capable of delivering light to and from asample are important for a practical application of Raman spectroscopy,e.g., in the field of medicine. In general, this can be accomplishedusing optical fibers. For example, low-OH fused silica core/fused silicaclad fibers can be implemented for this purpose, as described in M. Shimet al., “Development of an In Vivo Raman Spectroscopic System forDiagnostic Applications,” J Raman Spectrosc, Vol. 28, p. 131 (1997).However, the use of such fibers may also be problematic. The material ofthe fiber is Raman active. As the excitation light travels down thecore, a large fiber background signal (which can overlap the spectralfingerprint region of most materials) can be generated which propagatesalong this fiber. This background can be elastically scattered by thesample, and may reach the detector in the same or substantially similarmanner as the signal of interest. Further, a portion of the excitationlight can also be reflected from the sample, and may cause the same orsimilar effect in the fibers used for collection, as described in R. L.McCreery, “Raman Spectroscopy for Chemical Analysis, Chemical Analysis:A Series of Monographs on Analytical Chemistry and Its Applications,”John Wiley & Sons, Inc., Vol. 157, p. 420 (2000).

An intense luminescence generated in optical fibers transmitting laserlight is a drawback in the remote Raman spectroscopy, includingproviding catheter access to internal organs. This detrimentalbackground is associated with a shot noise (as described below) that cancompletely overwhelm Raman signals from the interrogated sample. Thisdeficiency can generally be overcome by employing separate fibers fordelivery of laser light to, and collecting the Raman-scattered lightfrom the tissue, along with filtering at the distal end of the opticalfiber probe. The delivery (or excitation) fiber is terminated with orregistered to a short-wavelength pass shown in FIG. 1B or band-passfilter that transmits the laser light to the tissue while blockingluminescence generated in the fiber as shown in FIG. 1A. The collectionfibers are preceded at the distal end by a long-wavelength pass as shownin FIG. 1B or notch filter that prevents elastically scattered laserlight from entering the fiber and generating additional background,while still transmitting the Raman scattered light from the sample asshown in FIG. 1C. Such filters can be of the dielectric, holographic, orabsorptive type.

While the above-described strategy has been used in the past, themajority of commercial Raman probes are very large and likelyinapplicable for endoscopic or angioscopic applications. Visionex, Inc.developed Raman probes with a diameter of ˜1 mm, as described in M. Shimet al., “Study of Fiber-Optic Probes for in Vivo Medical RamanSpectroscopy,” Appl Spectrosc, Vol. 53(6), p. 619 (1999). An opticalfiber probe has been described which is less than 3 mm in diameter, thathas been used to obtain high-quality in vivo Raman spectra of arterialand breast tissue, as described in J. T. Motz et al., “Optical fiberprobe for biomedical Raman spectroscopy,” Applied Optics, Vol. 43(3), p.542 (2004).

With respect to the detection of the electromagnetic radiation, a signalof a given intensity is likely associated with a certain level of noise.Such noise can be referred to as “shot noise,” and its amplitude may beequal to or approximately the square root of the detected signal.Therefore, the background that is generated in the fibers and gatheredby the detection system also contributes noise to the final signal ofinterest. It is possible that this noise may be greater in amplitudethan the Raman signal from the sample, thus resulting in mostly uselessdata with SNR<1. Furthermore, any additional non-Raman luminescencegenerated in the sample can also contribute to the shot noise. This hasgenerally prevented a successful application of an excitation withvisible lasers for investigating the biological samples.

Another source of background luminescence (e.g., noise) in Ramanspectroscopy measurements is provided in further optical processes (suchas fluorescence) from the sample itself. One possible way to circumventthis drawback is to employ pulsed lasers and time-gated detectionbecause Raman scattering likely takes place in timescales on the orderof femtoseconds (fs=10⁻¹⁵ s), while the fluorescence occurs on the orderof nanoseconds (ns=10⁻⁹ s) as shown in FIG. 3A. Therefore, if theremitted light is collected only from the time of arrival of the laserpulse at the sample until the start of fluorescence emission, themajority of this background signal can be avoided as shown in FIG. 4.This procedure has been exploited pursuant to the use of pulsed lasers,and has been used in open air geometries (i.e., without the use ofoptical fibers) for review of biological tissue, such as bone, asdescribed in M. D. Morris et al., “Kerr-gated time-resolved Ramanspectroscopy of equine cortical bone tissue,” Journal of BiomedicalOptics, Vol. 10(1) (2005), and bladder and prostate, as described in M.C. H. Prieto et al., “Use of picosecond Kerr-gated Raman spectroscopy tosuppress signals from both surface and deep layers in bladder andprostate tissue,” Journal of Biomedical Optics, Vol. 10(4), p. 044006(2005).

A development of catheters and endoscopes capable of delivering light toand from a sample is important for practical applications of Ramanspectroscopy such as, e.g., in the field of medicine. In general, thiscan be accomplished through the use of optical fibers. It is known thatlow-OH fused silica core/fused silica clad fibers can be used for thispurpose, as described in M. Shim et al., “Development of an In VivoRaman Spectroscopic System for Diagnostic Applications,” J RamanSpectrosc, Vol. 28, p. 131 (1997). However, the use of such fibers canalso be problematic. The material of the fiber is likely itself Ramanactive, and as the excitation light travels down the core a large fiberbackground signal, which overlaps the spectral fingerprint region ofmost materials, may be generated and propagates down the fiber. Thisbackground can be elastically scattered by the sample, and generallyreach the detector in the same manner as the signal of interest.Furthermore, a portion of the excitation light is further reflected fromthe sample, and can cause the same effect in the fibers used forcollection, as described in R. L. McCreery, “Raman Spectroscopy forChemical Analysis, Chemical Analysis: A Series of Monographs onAnalytical Chemistry and Its Applications,” John Wiley & Sons, Inc., NewYork, Vol. 157, p. 420, (2000).

One of the fundamental properties of a detection of the electromagneticradiation is that the signal of a given intensity is generally alwaysassociated with a certain level of noise. This is termed “shot noise,”and its amplitude is equal to the square root of the detected signal.Therefore, the background that is generated in the fibers, and gatheredby the detection system also contributes noise to the final signal ofinterest. It is often the case that this noise may be greater inamplitude than the Raman signal from the sample, resulting in uselessdata with SNR<1. As discussed above, this is generally circumvented bythe use of optical filters.

There is a need to overcome the deficiencies described herein above.

SUMMARY OF THE INVENTION

To address and/or overcome the above-described problems and/ordeficiencies, exemplary embodiments of systems and methods which can beused for receiving and/or analyzing information associated withelectromagnetic radiation, e.g., based on signals propagated via atleast one fiber arrangement.

Thus, according to an exemplary embodiment of the present invention, asystem can be provided which can have at least one fiber arrangement andat least one receiving arrangement. The fiber arrangement may haveoptical transmitting characteristics, and may be configured to transmitthere through at least one electromagnetic radiation and forward the atleast one electromagnetic radiation to at least one sample. At least oneportion of the fiber arrangement may be composed of or can includetherein sapphire, diamond, clear graphite, Chalcogenide, borosilicate,zirconium fluoride, silver halide, a liquid core light guide, a gas corelight guide, a hollow core waveguide, and/or a solid core photoniccrystal fiber. The receiving arrangement may be configured to receivethe electromagnetic radiation that is filtered and received from thesample.

The fiber arrangement can include therein at least one filteringarrangement. The fiber and filtering arrangements can be configured totransmit there through the electromagnetic radiation and forward theelectromagnetic radiation to the sample. The receiving arrangement caninclude therein at least one further filtering arrangement which may beadapted to filtered the received electromagnetic radiation. Thereceiving arrangement can be the further fiber arrangement which mayhave optical transmitting characteristics. The received electromagneticradiation can be a Raman radiation associated with the sample. A furtherarrangement can be provided which may be configured to house therein atleast one portion of the fiber arrangement. The sample may be providedat least partially within an anatomical structure.

The receiving arrangement may include a fiber arrangement which can becomposed of or include therein sapphire, diamond, clear graphite,Chalcogenide, borosilicate, zirconium fluoride, silver halide, a liquidcore light guide, a gas core light guide, a hollow core waveguide,and/or a solid core photonic crystal fiber. The fiber arrangement caninclude at least one first fiber which may have at least one firstfiltering characteristic that filter the electromagnetic radiation. Thereceiving arrangement may be configured to receive the electromagneticradiation that is filtered by the fiber and/or a second fiber which mayhave the second filtering characteristic that filter the electromagneticradiation. The fiber arrangement and the receiving arrangement may bethe same arrangements.

According to yet another exemplary embodiment of the present inventionat least one further fiber arrangement can be provided which isconfigured to receive the electromagnetic radiation that is filtered andreceived from the sample. This further fiber arrangement may be composedof or includes therein sapphire, diamond, clear graphite, Chalcogenide,borosilicate, zirconium fluoride, silver halide, a liquid core lightguide, a gas core light guide, a hollow core waveguide, and/or a solidcore photonic crystal fiber. Further, the fiber arrangement may includetherein at least one filtering arrangement, and the fiber and filteringarrangements may be are configured to transmit there through theelectromagnetic radiation and forward the electromagnetic radiation tothe sample. At least one filtering characteristic of the filteringarrangement can be provided by a fiber Bragg grating. The first fiberand/or the second fiber can be filtered based on the first filteringcharacteristic and/or the second filtering characteristic to prevent atleast one portion of the electromagnetic radiation having particularwavelengths from being forwarded therein.

According to still another exemplary embodiment of the presentinvention, the electromagnetic radiation can have at least onecharacteristic so as to reduce and/or substantially eliminate afluorescence from the sample. For example, the electromagnetic radiationmay cause a stimulated depletion of the fluorescence from the sample.Further, the electromagnetic radiation may photobleach the fluorescencefrom the sample.

In yet another further exemplary embodiment of the present invention, afirst optical fiber arrangement can be provided which may be configuredto propagate therethrough at least one first electromagnetic radiationto the sample provided at least partially within an anatomicalstructure, and received at least one second electromagnetic radiationfrom the sample. At least one second arrangement can be provided whichmay be configured to collect first portions of the secondelectromagnetic radiation and exclude second portions of the secondelectromagnetic radiation as a function of time.

For example, the first portions can include inelastic scatteringportions of the second electromagnetic radiation, and the secondportions may include fluorescent portions of the second electromagneticradiation. The second portions may further include a backgroundelectromagnetic radiation generated within the first arrangement. Thesecond portions can further include an elastically-scatteredelectromagnetic radiation reflected within the first arrangement and/orfrom the sample. In addition, the first portions may include a first setof signals and a second set of signals. The first set can be received atthe second arrangement at a time which is earlier than a time at whichthe second set is received at the second arrangement. The secondarrangement may be further configured to determine informationassociated with at least one depth of the sample as a function of thefirst and second sets of the signals. The first arrangement may beconfigured to allow at least some of the wavelengths of the firstelectromagnetic radiation to propagate therethrough at approximately thesame velocity. The anatomical structure may include a portion which hasa coronary artery.

According to still another exemplary embodiment of the presentinvention, the second characteristic of the second electromagneticradiation can be modulated. The second modulated electromagneticradiation can be compared with at least one third electromagneticradiation provided from the sample. Dissipation of heat from the portionof the optical fiber can be directed in a particular manner. The portionof the optical fiber can also be insulated, and/or may have aconductivity sufficient to change of the first characteristic throughoutthe optical fiber when applied at a discrete location.

Still another exemplary embodiment of system and method according to thepresent invention can be provided. For example, at least one fiberarrangement can be utilized (which has optical transmittingcharacteristics) that may include therein at least one filteringarrangement. The fiber arrangement and the filtering arrangement may beconfigured to transmit there through at least one electromagneticradiation, and forward the at least one electromagnetic radiation to atleast one sample. At least one receiving arrangement may be providedthat is configured to receive the electromagnetic radiation that isfiltered and received from the sample. At least one portion of the fiberarrangement may be composed of or includes therein sapphire, diamond,clear graphite, Chalcogenide, borosilicate, zirconium fluoride, silverhalide, a liquid core light guide, a gas core light guide, a hollow corewaveguide, and/or a solid core photonic crystal fiber.

According to another exemplary embodiment, a method can be provided forobtaining information associated with the sample. For example, at leastone first electromagnetic radiation can be forwarded to the sample viaat least one optical fiber. At least one first characteristic of atleast one portion of the optical fiber can be controlled so as to modifyat least one second characteristic of at least one secondelectromagnetic radiation generated within the optical fiber. The secondelectromagnetic radiation can be associated with the firstelectromagnetic radiation.

The controlling procedure can include an increase of energy of one ormore molecules that reside in the portion of the optical fiber. Thefirst characteristic can include temperature. Further, the controllingprocedure may includes an excitation of an optical illumination of theportion of the optical fiber, and/or a generation of an electrical fieldat approximately the portion of the optical fiber. In addition, it ispossible to reduce or remove a background radiation associated with thesecond electromagnetic radiation. Further, it is possible to modulatethe second characteristic of the second electromagnetic radiation. It isalso possible to compare the second modulated electromagnetic radiationwith at least one third electromagnetic radiation provided from thesample. In addition, a dissipation of heat can be directed from theportion of the optical fiber in a particular manner. The portion of theoptical fiber may be insulated, and/or can have a conductivitysufficient to effectuate a change of the first characteristic throughoutthe optical fiber when applied at a discrete location.

According to still another exemplary embodiment of the presentinvention, a system can be provided for obtaining information associatedwith at least one sample. For example, at least one first radiationgenerating arrangement can be provided which may be configured toforward at least one first electromagnetic radiation to the sample viaat least one optical fiber. At least one second arrangement may also beprovided which may be configured to control at least one firstcharacteristic of at least one portion of the optical fiber so as tomodify at least one second characteristic of at least one secondelectromagnetic radiation generated within the optical fiber. The secondelectromagnetic radiation may be associated with the firstelectromagnetic radiation.

According to a still further exemplary embodiment of the presentinvention, an arrangement can be provided for obtaining informationassociated with at least one sample. The arrangement can include a firstmodule, which when executed by a processing arrangement, may cause atleast one radiation generating arrangement to forward at least one firstelectromagnetic radiation to the sample via at least one optical fiber.The arrangement can include a second module, which when executed by aprocessing arrangement, may control at least one first characteristic ofat least one portion of the optical fiber so as to modify at least onesecond characteristic of at least one second electromagnetic radiationgenerated within the optical fiber. The second electromagnetic radiationcan be associated with the first electromagnetic radiation.

In yet another exemplary embodiment of the present invention, a methodcan be provided. In this exemplary method at least one electromagneticradiation can be transmitted through at least one fiber arrangement andat least one filtering arrangement. The fiber arrangement may haveoptical transmitting characteristics and include therein the filteringarrangement. The electromagnetic radiation may be forwarded to at leastone sample. The fiber arrangement may include at least one first fiberwhich can have characteristics that filter the electromagneticradiation. The electromagnetic radiation can be received from the sampleand filtered using at least one receiving arrangement. At least oneportion of the fiber arrangement can be composed of and/or can includetherein sapphire, diamond, clear graphite, Chalcogenide, borosilicate,zirconium fluoride, silver halide, a liquid core light guide, a gas corelight guide, a hollow core waveguide, and/or a solid core photoniccrystal fiber.

These and other objects, features and advantages of the presentinvention will become apparent upon reading the following detaileddescription of embodiments of the invention, when taken in conjunctionwith the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

Further objects, features and advantages of the invention will becomeapparent from the following detailed description taken in conjunctionwith the accompanying figures showing illustrative embodiments of theinvention, in which:

FIG. 1A is an exemplary graph illustrating an idealized transmissionprofile for band-pass and notch filters for use in optical fiber probesfor Raman spectroscopy;

FIG. 1B is an exemplary graph illustrating an idealized transmissionprofile for short-pass and long-pass filters for use in the opticalfiber probes for the Raman spectroscopy;

FIG. 1C is an exemplary graph illustrating actual and idealizedtransmission profiles for collection and excitation filters for use inthe optical fiber probes for the Raman spectroscopy;

FIG. 2 is a block and procedural diagram illustrating exemplary effectsof certain filters which can be used to reduce or eliminate theluminescence generated in the optical fibers of Raman probes inaccordance with an exemplary embodiment of the present invention;

FIG. 3A is a graph illustrating typical times for photo-molecularinteractions of a fluorescence signal when using a picosecond pulsedlaser for the excitation;

FIG. 3B is a graph illustrating typical times for photo-molecularinteractions of a laser pulse, Raman signal and Rayleigh signal whenusing a picosecond pulsed laser for the excitation;

FIG. 4 is a graph of an exemplary time sequence for collected time-gatedsignals when using a pulsed laser to minimize collection of emittedfluorescence according to the an exemplary embodiment of the presentinvention;

FIG. 5 is a graph of an exemplary background generated in optical fibersscales as the square of the fiber's numerical aperture according toanother exemplary embodiment of the present invention;

FIG. 6 is a block diagram of a system according to an exemplaryembodiment of the present invention which uses a dual-clad fiber forRaman spectroscopy;

FIG. 7 is a block diagram of a system according to another exemplaryembodiment of the present invention which uses fiber Bragg gratings asfilters in exemplary Raman probes;

FIG. 8 is a side view of an exemplary embodiment of a Raman probeaccording to the present invention which uses a mirror or reflector todirect both the laser light and Raman scattered photons;

FIG. 9 is a side view of a further exemplary embodiment of a filteraccording to the present invention which can be helpful in removing thefiber background and laterally directing the light;

FIG. 10A is a side view of one exemplary embodiment of the filter whichuses a grating to spatially filter the light and eliminate the fiberbackground;

FIG. 10B is a side view of another exemplary embodiment of the filterwhich uses the grating to spatially filter the light and eliminate thefiber background; and in which a dual-clad fiber can be used fordelivery and collection;

FIG. 11 is a graph of an exemplary effect of a temperature on the ratioof emitted anti-Stokes and Stokes Raman photons;

FIG. 12 is a general block diagram of a procedure for implementingtime-gated techniques in the Raman spectroscopy to eliminate collectionof sample fluorescence according to an exemplary embodiment of thepresent invention;

FIG. 13A is an illustration of a cross-section of a first exemplaryembodiment of a fiber arrangement according to the present inventionwhich includes an integral insulation;

FIG. 13B is an illustration of a cross-section of a second exemplaryembodiment of the fiber arrangement according to the present inventionwhich includes the integral insulation;

FIG. 14 is a diagram of n exemplary embodiment of a cooling methodaccording to the present invention using an exemplary cooling mechanismhoused within the apparatus which may include one or more opticalfibers; and

FIG. 15 is an illustration of a cross-section of a third exemplaryembodiment of the fiber arrangement according to the present inventionwhich includes the integral insulation.

Throughout the figures, the same reference numerals and characters,unless otherwise stated, are used to denote like features, elements,components or portions of the illustrated embodiments. Moreover, whilethe subject invention will now be described in detail with reference tothe figures, it is done so in connection with the illustrativeembodiments. It is intended that changes and modifications can be madeto the described embodiments without departing from the true scope andspirit of the subject invention as defined by the appended claims.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION Summary ofExemplary Optical Fiber Probe Design

Exemplary Fiber Selection

Catheters and endoscopes capable of delivering light to and from asample are important for a practical application of Raman spectroscopy,e.g., in the field of medicine. In general, this can be accomplishedusing optical fibers. For example, low-OH fused silica core/fused silicaclad fibers can be implemented for this purpose, as described in M. Shimet al., “Development of an In Vivo Raman Spectroscopic System forDiagnostic Applications,” J Raman Spectrosc, Vol. 28, p. 131 (1997).However, the use of such fibers may also be problematic. The material ofthe fiber is Raman active. As the excitation light travels down thecore, a large fiber background signal (which can overlap the spectralfingerprint region of most materials) can be generated which propagatesalong this fiber. This background can be elastically scattered by thesample, and may reach the detector in the same or substantially similarmanner as the signal of interest. Further, a portion of the excitationlight can also be reflected from the sample, and may cause the same orsimilar effect in the fibers used for collection, as described in R. L.McCreery, “Raman Spectroscopy for Chemical Analysis, Chemical Analysis:A Series of Monographs on Analytical Chemistry and Its Applications,”John Wiley & Sons, Inc., Vol. 157, p. 420 (2000).

With respect to the detection of the electromagnetic radiation, a signalof a given intensity is likely associated with a certain level of noise.Such noise can be referred to as “shot noise,” and its amplitude may beequal to or approximately the square root of the detected signal.Therefore, the background that is generated in the fibers and gatheredby the detection system also contributes noise to the final signal ofinterest. It is possible that this noise may be greater in amplitudethan the Raman signal from the sample, thus resulting in mostly uselessdata with SNR<1.

It is possible to control the amplitude of this fiber background byselecting the appropriate numerical aperture (NA) fibers. For example,as shown in the graph of FIG. 5, the intensity of the background can bescaled as NA2, as described in J. Ma et al., “Fiber Raman BackgroundStudy and its Application in Setting Up Optical Fiber Raman Probes,”Applied Optics, Vol. 35(15), p. 2527 (1996). Thus, a selection of alower NA can reduce the background signal. However using such procedure,it may generally not be sufficient to reduce the shot noise to amanageable level. Furthermore, lower NA fibers can result in a lowercollection efficiency, thereby likely reducing the signal of interest.

According to an exemplary embodiment of the present invention, furthermaterials and designs not previously available may provide superioroptical fibers that can produce minimal background, thereby increasingSNR. These may include, but are not limited to, e.g.:

-   -   Alternate materials: sapphire, diamond or clear graphite,        Chalcogenide, zirconium fluoride, and silver halide    -   Liquid core light guides (e.g. DuPont's Teflon AF tubing) filled        with water, deuterium, or other liquids with low Raman activity    -   Gas core light guides    -   Hollow core waveguides: metallic, dielectric (c.f. OmniGuide,        http://www.omni-guide.com/), photonic crystal (“holey”) fiber        (c.f. Crystal Fibre, http://www.blazephotonics.com/), or light        guiding capillary tubing        (c.f.www.polymicro.com/products/capillarytubing/products        capillaryt ubing_ltsp.htm)    -   Solid core photonic crystal fiber (c.f. Crystal Fibre,        http://www.blazephotonics.com/)

In addition, dual (or double) clad fibers, e.g., the solid core andcladding type or the photonic crystal type, can provide a particulargeometry for a remote Raman spectroscopy. Instead of implementing theconventional n-around-1 geometry with a central excitation fiber and nsurrounding collection fibers, the central core of a dual clad fiber canbe used for an excitation, while the inner cladding can be forcollecting the Raman scattered light. Particular filters can beregistered with or written onto the core and inner clad of such fibersas shown in the exemplary embodiment of the system illustrated in FIG.6, and as further discussed herein below.

In addition, dual (or double) clad fibers, e.g., the solid core andcladding type or the photonic crystal type, can provide a particulargeometry for a remote Raman spectroscopy. Instead of implementing theconventional n-around-1 geometry with a central excitation fiber and nsurrounding collection fibers, the central core of a dual clad fiber canbe used for an excitation, while the inner cladding can be forcollecting the Raman scattered light. Particular filters can beregistered with or written onto the core and inner clad of such fibersas shown in the exemplary embodiment of the system illustrated in FIGS.6 and 9, and as further discussed herein below.

Filtering Techniques

Even with the proper selection of fiber material/design, significantbackground signal may still compromise SNR, and detract from an accurateanalysis of the sample's Raman spectrum. In such cases, it may bepreferable to provide one or more filters at the distal ends of theexcitation and collection fiber(s). Thus, fiber Bragg gratings can beprovided into the core at the end of the optical fibers, as shown in ablock diagram of FIG. 7. The fibers can be single-mode or multi-modefibers, and may include step-index or graded-index cores. These gratingscan be specifically tuned to reject or block various wavelength regions,and thus can be used in stead of or in addition to the traditionalholographic or dielectric filters. A short-wavelength pass or band-passfilter can be provided into the delivery fiber to reject luminescencegenerated in the fiber and pass the laser light to the sample. Thecollection fiber(s) can include a notch-type or long-wavelength passfilter to at least partially block the elastically scattered light fromthe sample, and pass the Raman scattered light from the sample.

Various types of reflectors (e.g. dielectric stack filters) can be usedto simultaneously filter the optical signals and direct this light tothe appropriate location (e.g. side/lateral/circumferential-viewinggeometries). For example, a fiber registered with, or monolithicallyterminated with a ball (or other type) lens can be provided, an exampleof which is shown in FIG. 8, the details of which shall be discussedherein below. Such exemplary lens can be is polished to an angle canhave a mirror on the polished surface to deflect the beam at an angle.The mirror can be replaced or modified by a filter may be deposited onor placed behind (and parallel to) the polished surface to deflect theappropriate wavelengths, the example of which is shown in FIG. 9, anddescribed in further detail below.

Various types of reflectors (e.g. dielectric stack filters) can be usedto simultaneously filter the optical signals and direct this light tothe appropriate location (e.g. side/lateral/circumferential-viewinggeometries). For example, a fiber registered with, or monolithicallyterminated with a ball (or other type) lens can be provided, an exampleof which is shown in FIG. 5, the details of which shall be discussedherein below. Such exemplary lens can be is polished to an angle and canhave a mirror on the polished surface to deflect the beam at an angle.The mirror can be replaced or modified by a filter which may bedeposited on or placed behind (and parallel to) the polished surface todeflect the appropriate wavelengths, the example of which is shown inFIG. 8, and described in further detail below.

Filtering of the signals can also be accomplished by spectralseparation. Gratings at the distal end of the fibers can be used toselectively deflect appropriate wavelengths. For example, the polishedsurface of the above mentioned lens can be imprinted with a grating,thereby deflecting the desired wavelengths with an angular spread thatis spectrally centered orthogonal to the long axis of the optical fiber,as shown in the arrangements of FIGS. 10A and 10B, and described in moredetail below. The undesired wavelengths can be blocked by absorptive (orreflective) elements deposited on the exit surface of the lens lateralto the transmission window. This exemplary configuration can be suitedfor the excitation path.

A temperature modulation of the optical fibers can assist in spectralfiltering. The ratio of Raman scattered photons that are anti-Stokesshifted (e.g., to shorter wavelengths) relative to those which areStokes shifted (e.g., to longer wavelengths) from the excitationwavelength can be increased with temperature, as shown in the graph ofFIG. 3, e.g., associated with number of molecules in excited vibrationalstates according to the Boltzmann distribution

$\begin{matrix}{\frac{I_{AS}}{I_{S}} = {\left( \frac{v_{i} + v_{vib}}{v_{i} - v_{vib}} \right)^{4}^{{- {hv}_{vib}}/{kT}}}} & (1)\end{matrix}$

where I_(AS) and I_(S) are the intensities of the anti-Stokes and Stokesemitted light, respectively, v_(i) and v_(vib) are the frequency of theexcitation and emitted photons, respectively, h is Planck's constant, kis the Boltzmann constant, and T is temperature. Temperature modulation(optically or electrically) of the excitation fiber will create a shiftin the anti-Stokes/Stokes ratio of Raman scattered photons from thefiber, allowing a temporal frequency filter to separate the fiberbackground photons from sample Raman photons which are not thermallymodulated.

Exemplary Minimization of Non-Raman Sample Luminescence

Certain applications of Raman spectroscopy can be inhibited by anintense fluorescence from the sample and its associated shot noise whichcan overwhelm the observation of the Raman emission of interest, ofteneven in the presence of resonance enhancement of the Raman signal. Thisis particularly the case for a biological Raman spectroscopy where theRaman scattering may not typically be detected with a visibleexcitation. Ultraviolet excitation allows for the observation of theRaman emission because it is sufficiently spectrally separated from thefluorescence. However, these exemplary wavelengths are mutagenic andhave very limited penetration in tissue. And even with UV excitation,the problems of fiber background persist. Excitation by pulsed lasershas at least two potential mechanisms to reduce collection offluorescent signals: photo-bleaching and time resolution.

Photo-Bleaching

The increased temporal energy density of pulsed lasers causesphoto-bleaching of the tissue autofluorescence due to depopulation ofthe ground state, thereby reducing the confounding emission. Theduration between fs or picosecond (ps=10⁻¹² s) pulses can allow asufficient diffusion of heat induced by absorption to prevent thermaldamage, especially in regions with natural cooling mechanisms, such asblood flow in the vascular system. Studies have shown that significantphoto-bleaching can occur below the energy densities that result in ahistological evidence of arterial tissue damage, even in the absence ofblood flow, as described in J. T. Motz, “Development of In Vivo RamanSpectroscopy of Atherosclerosis,” Ph.D. Thesis, Massachusetts Instituteof Technology, Cambridge, 2003.

Time Gating

Pulsed lasers generally allow gating of collection using certaintechniques due to the temporal difference in various photo-molecularinteractions. Resonance Raman scattering, which uses the absorption andinteraction with the excited electronic states may have emissionlifetimes on the order of 10⁻¹⁴ s (10 fs); non-resonant Raman scatteringoccurs at even faster rates. In contrast, the majority of fluorescenceemission occurs with lifetimes on the order of nanoseconds. By usingpicosecond pulsed lasers, these signals can be temporally separated toeliminate collection of interfering fluorescence emission, as shown inthe graphs of FIGS. 3A, 3B and 4. Preferably, pulse durations of ˜10 pscan be employed to provide sufficiently narrow excitation line widthswhich can maintain a Raman spectral resolution. The detection system canthen be configured to collect light from the arrival of the excitationpulse for a duration that ends prior to some or all of the fluorescenceemission. This provides for a collection of substantially all of theRaman light with possibly a small contamination of the backgroundsignal. This exemplary embodiment of a procedure according to thepresent invention can provide sufficient fluorescence elimination toenable the visible excitation, thereby taking advantage of the v⁴dependence of the Raman scattering intensity (see Eq. 1 above).

Exemplary Minimization of Fiber Generated Background

In addition, possibly due to the finite time of the photon propagation(˜1 foot/ns), it is also possible to eliminate at least a majority ofthe fiber background generated in the excitation fiber via time gatingusing an optical fiber Raman probe, e.g., several meters in length. Thefiber background generated in the excitation fiber should be reflectedfrom the sample, and gathered by the collection fibers for delivery tothe detector. If the detector is not gated on, e.g., until slightlyafter the excitation pulse reaches the tissue, a large fraction of thefiber background may not be detected because the specular reflection ofthis signal may occur before the Raman emission. This greatly simplifiesthe filtering requirements in the optical fiber probe itself.

Exemplary gating procedures can include optical or electronic-relatedprocedures as shown an exemplary functional block diagram of FIG. 5.Exemplary optical procedures can include the use of Kerr cells andPockel cells. Exemplary electronic gating can include the use of streakcameras, rapid (ns) response photodiode arrays, micro-channel platedetectors, or homodyne detection. The inclusion of optical fibers maypossibly utilize a dispersion compensation or the use of dispersion-freefibers.

Exemplary Optical Fiber Probe Arrangement and Process

A graph 100 of FIG. 1A shows an exemplary graph of an idealized filtertransmission profile for use in an optical fiber Raman probe. Forexample, the laser profile 101 is shown at 0 cm⁻¹. The band-pass filterwhich passes the laser light but blocks all other wavelengths, includingspontaneous emission from the laser and background luminescencegenerated in optical fibers, can be placed at the distal end of theexcitation fiber and/or provided into the fiber as a Bragg grating. Thisexemplary filter enables an excitation of the sample but likely preventsthe fiber background from reflecting from the sample and entering thecollection path. The exemplary profile 102 of the signal passed throughthe band-pass filter is also shown in FIG. 1A. The notch filter, whichcan transmit wavelengths that may be longer and/or shorter than that ofthe laser, may be placed at the distal end of the collection fibers orprovided therein as Bragg gratings. This notch filter can prevent theelastically scattered laser light from entering the collection, therebypreventing the generation of additional fiber background. The use of thenotch-type filter can also allow the Raman probe to be used for theobservation of anti-stokes Raman scattering. An exemplary profile 103 ofthe signal passing through the notch filer is shown in FIG. 1A.

A graph 105 of FIG. 1B shows the transmission profiles of two furthertypes of filters which can be utilized instead of or in conjunction withthe filters described above with reference to FIG. 1A. A short-passfilter that can transmit the laser and may reflect longer wavelengthscan take the place of the band-pass filter described above at the distalend of the excitation fiber. The exemplary profile 106 of the signalpassing through the short-pass filter is shown in FIG. 1B. A long-passfilter which can reflect the laser wavelength and may transmit thelonger wavelengths can be uses as an alternative to the notch filter atthe distal end of the collection fiber(s). The exemplary profile 107 ofthe signal passing through the long-pass filter is shown in FIG. 1B.

A graph 110 of FIG. 1C shows examples of the transmission curves for theshort-pass filter and the long-pass filter that can be realized withdielectric filters. The exemplary profile 112 of the signal passingthrough an excitation filter, and the exemplary profile 115 of thesignal passing through a collection filter are shown in FIG. 1C.

FIG. 2 depicts a functional block diagram of an exemplary embodiment ofa procedure according to the present invention in which the signalsinteract with the filters that can be used at the distal end of a Ramanprobe. For example, on the left-hand side of FIG. 2, an interactionwhich uses unfiltered fibers is shown. For example, an excitation light205 from a laser source or a filtered broadband source can be coupledinto unfiltered excitation fiber 210. As this light 205 travels down afiber 210, a background luminescence 215 can be generated, which thenalso travels down the fiber 210, subsequently exiting from the fiber210, and impacting the sample 220. The fiber background 215 can bediffusely scattered and/or specularly reflected from the sample 220.This reflected light 225 can enter an unfiltered collection fiber 240,and possibly be transmitted to a detector 250. A portion of the laserlight 205 can also be diffusely scattered and/or specularly reflectedfrom the sample 220, and enter the collection fiber 240. Such reflectedlaser light 235 can generate a further fiber luminescence 245 in thecollection fiber(s) 240 which may be transmitted to the detector 250.The Raman signal 230 generated in the sample can also be transmitted tothe detector 250 through the collection fiber 240.

The right-hand side of FIG. 2 shows the exemplary functionality of thefilters which can be used in a Raman probe. The light 205 from source200 can enter the excitation fiber 210, and may be transmitted throughfilter 255 to the sample 220. The fiber background 215 of the left-handside of FIG. 2 can be blocked by the filter 255, which can be ashort-pass filter and/or band-pass filter. The background 215 does not,therefore, have to reach the sample 220 or the detector 250. Thereflected laser light 235 can be blocked from entering the collectionfiber 240 by the filter 260, which can be a notch filter or a long-passfilter, thereby preventing generation of fiber luminescence in thecollection fiber 240. The generated sample Raman can be passed by thefilter 260 for a transmission to the detector 250 by the collectionfiber 240.

FIG. 5 shows an exemplary graph 500 of a Raman spectra of two differentfused silica optical fibers with different NAs. The more intensespectrum 510 can be generated by a fiber with NA=0.26, while the weakerspectrum 520 may be generated from a fiber with NA=0.12. In this manner,the NA² dependence of background intensity can be demonstrated.

FIG. 6 shows a block diagram of an exemplary embodiment of a systemaccording to the present invention which uses a double fiber or adual-clad fiber for the Raman spectroscopy. For example, the light froma laser 600 can be split by a beam splitter or deflected by a dichroicmirror or a filter such that the laser light is directed to optics 610for coupling into a central core 635 of a dual-clad fiber 615.Illumination and collection optics 620 can forward the laser to a sample625, and collect the Raman scattered light returning from the sample625. The Raman scattered light can be provided to an inner cladding 640of the dual-clad fiber 615. The light emerging from the fiber 615 can bedeflected by a beam splitter or dichroic filter 605 and directed todetector 630. The dichroic filter can be a notch filter, a band-passfilter, a long-pass filter, or a short-pass filter possibly oriented inan appropriate manner. The filter can be of the holographic, dielectricor other type. The appropriate transmission filters can be placed on thedistal end of the fiber sections or placed in registration with them.Alternately, fiber Bragg gratings can be provided into the fiber 615 toprovide certain filtering capabilities.

FIG. 7 a block diagram of another exemplary embodiment of a systemaccording to the present invention which uses fiber Bragg gratings asthe filters in the optical fiber probes for Raman spectroscopy. Forexample, the light from a laser 700 can be provided to an excitationfiber 710 by coupling optics 705. The background luminescence generatedin the fiber 710 can be reflected by the fiber Bragg grating 715 toprevent it from reaching a sample 725. The fiber Bragg grating 715 canbe a band-pass grating or a short-pass grating. The laser light may betransmitted to the sample 725 via illumination and collection optics720. The Raman scattered light can be provided to a fiber 735 byillumination and collection optics 720. Rayleigh or diffusely scatteredlaser light is prevented from entering fiber 735 by fiber Bragg grating730 which can be of the notch- or long-pass type. The transmitted signalmay then be provided to a detector 740.

FIG. 8 shows a side view of a Raman probe according to an exemplaryembodiment of the present invention. For example, the probe can bemodular, e.g., distal optics 810 may be separate units from the opticalfibers 805 and 830, and/or monolithic where the optics 810 may becreated by fusing and shaping the distal end of the fibers. A laserlight 800 may travel down an excitation fiber 805 with the appropriatefiltering, and enter the distal optics 810 which could be ahemi-spherical lens or another type of a lens. The optics 810 aresupported by a reflector which can redirect the laser light 800 to aside for the illumination of the sample 820. The generated Ramanscattered light may be gathered by the optics 810, and directed by areflector 815 to an appropriately filtered collection fiber(s) 830.

FIG. 9 shows a side view of another exemplary embodiment of the Ramanprobe of the present invention, in which a filter may be used toredirect the laser light from a modular or monolithic excitation fiber.A laser light 900 can be transmitted through a fiber 905 to distaloptics 910 which may be supported by a dichroic filter that passes thefiber background through the front of the probe, and can deflect thelaser to a sample 920 on the side. Raman scattered light 925 is gatheredby optics 910, passed through dichroic filter 915 and reflected by amirror 930 to be directed into a collection fiber 935. The filter 915can also reflect the Rayleigh scattered laser light, thereby likelypreventing the generation of a fiber background in the collection fiber935. Alternately, collection fiber 935 could be angle cleaved such thatthe Raman scattered light is directed into the fiber through totalinternal reflection, without the use of the mirror 930.

FIGS. 10A and 10B show block diagrams of two versions of still anotherexemplary embodiment of a Raman probe. For example, in one exemplaryversion shown in FIG. 10A, a grating is used only for the excitationfiber. The distal optics can be supported by a grating which can, in oneexemplary approach, be stamped onto the optics. A laser light 1000traveling along a fiber 1005 can enters distal optics 1010, and may bedeflected by a grating 1015 to a sample 1030. A fiber background 1020can be deflected at a different angle, and prevented from reaching thesample by a reflector or an absorbing layer 1025 placed on a lateralface of the optics 1010. A separate path may be used for the collection.In another exemplary version shown in FIG. 10B, a dual clad fiber (asshown in FIG. 6) can be used. In this exemplary version, an absorber orreflector is not placed on or in the optics 1010. Similarly to thepreviously-described version, the laser can travel along the core of thedual-clad fiber 1005, and may be deflected by the grating 1015 to thesample 1030. The fiber background 1020 can be deflected to a morelateral position away from the illuminated area. A Raman scattered light1032 can be gathered by the collection optics 1010, and deflected to theinner cladding 1035 of the dual-clad fiber by grating 1015.

FIG. 11 shows a graph providing an exemplary ratio of anti-Stokes toStokes shifted Raman as described above in Equation 1. The modulation ofthe temperature, optically and/or electrically, can shift the amount ofRaman emitted photons back and forth from anti-Stokes to Stokes shiftedemission, thereby likely producing an amplitude modulation of the fiberbackground. The signal from the tissue would not be modulated, andtherefore such signal can be differentiated from the fiber background.

In certain cases where the environment surrounding the optical fiber aresensitive to temperature changes, the protection of the environment maybe at issue. This can be addressed, e.g., by insulating the heatingelement and fiber from the surrounding environment, and/or providing acooling mechanism. Such cooling mechanisms could be integral to thefiber system or provided externally thereto. According to one exemplaryembodiment of the present invention, such fiber should have a sufficientconductivity to provide sufficient modulation frequencies. However, theconductivity of the cooling medium can be such that it does not transferheat to the surrounding environment. According to one exemplaryembodiment of an external cooling mechanism of the present invention, itis possible to provide a saline flush around the fiber to dissipate heatin the environment. Exemplary embodiments of fiber arrangements whichinclude integral insulation are shown in FIGS. 13A, 13B and 15, andexemplary embodiments of a cooling method according to further exemplaryembodiments of the present invention is shown in FIG. 5.

For example, FIG. 13A shows a cross-section of a first exemplaryembodiment of the fiber arrangement according to the present inventionwhich includes an integral insulation. For example, the optical fiber1300 can be heated electrically using a heating element 1305, and thegenerated heat may be confined to the fiber 1300 through an insulatingmaterial 1310. A similar insulating arrangement, e.g., a secondexemplary embodiment of the fiber arrangement according to the presentinvention as shown in FIG. 13B, can be employed by optically heating thefiber 1300, where the heating element 1305 is not shown.

FIG. 14 shows an exemplary embodiment of a cooling method according tothe present invention which can utilize an exemplary cooling mechanismhoused within the exemplary apparatus that may include one or moreoptical fibers 1400. For example, a liquid transfer system can beincluded within the apparatus to shield the environment from the heatingof the optical fiber(s) 1400, and be transmitted via a circulationelement 1405 and around distal optics 1410. Liquids such as water orthose with low conductivity and low viscosity can be used for suchcooling so that rapid flow and minimal heat transfer can be maintained.

FIG. 15 shows a cross-section of a third exemplary embodiment of thefiber arrangement 1520 according to the present invention which includesthe integral insulation. This exemplary fiber arrangement 1520 includesa separate cooling element 1515 which is provided in the fiberarrangement 1520 to maintain an appropriately low temperature at theboundary between the arrangement and the environment. For example, thecooling element 1515 can encompass the fiber 1500, the heating element1505 and the insulating material 1510.

Exemplary Minimization of Non-Raman Sample Luminescence

FIGS. 3A and 3B show graphs 300, 305 of exemplary time sequences forseveral photo-molecular interactions in a biological tissue, e.g.,modeling the remitted light along with an incident laser pulse. Thesimulation assumed a picosecond (10⁻¹² s FWHM) pulsed laser 307 with an80 MHz repetition rate and a fluorescence emission 301 with a lifetimewhich decays as e^(−t/τ), where τ is the fluorescence lifetime, and maybe assumed to be 2 ns. For example, the remitted Rayleigh scatteredlight 309 was assumed to follow a t^(−3/2) profile, while remitted Ramanphotons 306 were modeled with a t^(−1/2) profile, as described in N.Everall et al., “Picosecond time-resolved Raman spectroscopy of solids:Capabilities and limitations for fluorescence rejection and theinfluence of diffuse reflectance,” Applied Spectroscopy, Vol. 55(12), p.1701 (2001). The graph 300 of FIG. 3A shows 3 successive exemplary laserpulses and the Raman and Rayleigh scattered light, along with thefluorescence, all of which were normalized to their maximum signal. Onthe scale shown in FIG. 3A, the fluorescence decay can be visualized;however, the laser pulse 307 may be indistinguishable from the Rayleighre-emission 309 and the Raman re-emission 306. The graph 305 of FIG. 3Ashows a magnification of one pulse of the graph 300. In FIG. 3B, theremitted Rayleigh scattered light 309 can be seen as closely followingthe laser pulse 307, while the Raman scattering 306 emerges from thetissue with a slight delay, and before the peak of the fluorescenceemission 301.

FIG. 4 shows a graph of an exemplary potential time sequence accordingto an exemplary embodiment of the present invention for avoiding acollection of fluorescence from samples. For example, the laser pulse(solid line) 405 is followed by the Raman scattering (dashed line) 410as described above with reference to FIGS. 3A and 3B. The fluorescencesignal 415 can be slightly delayed, and may continue for a particularperiod of time which may be shorter than the duration between the laserpulses. A gating mechanism, which can be, but is not limited to, e.g., aKerr or Pockel cell or a gated optical imager, may be opened for theduration of the laser pulse or slightly longer to allow for a collectionof the Raman scattered light. The gate can then be closed before thefluorescence emission peaks, thereby likely preventing a detection ofsuch unwanted signal. The gate can be reopened at the next pulse.

FIG. 12 shows a block diagram of a system according to an exemplaryembodiment of the present invention for obtaining time gatedmeasurements which can be used to minimize collection of thefluorescence emitted from a sample being examined for the Ramanspectroscopy. For example, a laser 1200 can provide a laser light to afiber 1205, and directed to a sample 1210. The emitted luminescence maybe transmitted by appropriate collection optics and collection fiber(s)1215 to collimating optics 1220. The collimated light may then be passedthrough a triggered gating mechanism 1230 which mat be triggered by anoptical or electrical pulse 1225 from the laser 1200 that can open thegate for the duration of the laser pulse and potentially for a certainperiod of time thereafter. The transmitted light can then be transmittedto a spectrometer/detector for evaluation.

The foregoing merely illustrates the principles of the invention.Various modifications and alterations to the described embodiments willbe apparent to those skilled in the art in view of the teachings herein.Indeed, the arrangements, systems and methods according to the exemplaryembodiments of the present invention can be used with imaging systems,methods and procedures, and for example with those described inInternational Patent Application PCT/US2004/029148, filed Sep. 8, 2004,U.S. patent application Ser. No. 11/266,779, filed Nov. 2, 2005, andU.S. patent application Ser. No. 10/501,276, filed Jul. 9, 2004, thedisclosures of which are incorporated by reference herein in theirentireties. It will thus be appreciated that those skilled in the artwill be able to devise numerous systems, arrangements and methods which,although not explicitly shown or described herein, embody the principlesof the invention and are thus within the spirit and scope of the presentinvention. In addition, to the extent that the prior art knowledge hasnot been explicitly incorporated by reference herein above, it isexplicitly being incorporated herein in its entirety. All publicationsreferenced herein above are incorporated herein by reference in theirentireties.

1. A system, comprising: at least one fiber arrangement includingoptical transmitting characteristics, configured to transmit therethrough at least one electromagnetic radiation and forward the at leastone electromagnetic radiation to at least one sample, wherein at leastone portion of the at least one fiber arrangement is composed of orincludes therein at least one of sapphire, diamond, clear graphite,Chalcogenide, borosilicate, zirconium fluoride, silver halide, a liquidcore light guide, a gas core light guide, a hollow core waveguide, or asolid core photonic crystal fiber; and at least one receivingarrangement configured to receive the electromagnetic radiation that isfiltered and received from the at least one sample.
 2. The systemaccording to claim 1, the at least one fiber arrangement includingtherein at least one filtering arrangement, and wherein the at least onefiber arrangement and the filtering arrangement are configured totransmit there through the at least one electromagnetic radiation andforward the at least one electromagnetic radiation to the at least onesample.
 3. The system according to claim 1, wherein the at least onereceiving arrangement includes therein at least one further filteringarrangement which is adapted to filtered the received at least oneelectromagnetic radiation.
 4. The system according to claim 3, whereinthe at least one receiving arrangement is at least one further fiberarrangement which has optical transmitting characteristics.
 5. Thesystem according to claim 1, wherein the received at least oneelectromagnetic radiation is a Raman radiation associated with the atleast one sample.
 6. The system according to claim 1, further comprisinga further arrangement configured to house therein at least one portionof the at least one fiber arrangement.
 7. The system according to claim1, wherein the at least one sample is provided at least partially withinan anatomical structure.
 8. The system according to claim 1, wherein theat least one receiving arrangement includes a fiber arrangement which iscomposed of or includes therein at least one of sapphire, diamond, cleargraphite, Chalcogenide, borosilicate, zirconium fluoride, silver halide,a liquid core light guide, a gas core light guide, a hollow corewaveguide, or a solid core photonic crystal fiber.
 9. The systemaccording to claim 1, wherein the at least one fiber arrangementincludes at least one first fiber which has at least one first filteringcharacteristic that filter the electromagnetic radiation, and whereinthe at least one receiving arrangement is configured to receive theelectromagnetic radiation that is filtered by at least one of the atleast one first fiber or at least one second fiber which has the atleast one second filtering characteristic that filter the at least oneelectromagnetic radiation.
 10. The system according to claim 1, whereinthe at least one fiber arrangement and the at least one receivingarrangement are the same. 11-12. (canceled)
 13. A system, comprising: atleast one fiber arrangement which has optical transmittingcharacteristics, the at least one fiber arrangement including therein atleast one filtering arrangement, wherein the at least one fiberarrangement and the at least one filtering arrangement are configured totransmit there through at least one electromagnetic radiation andforward the at least one electromagnetic radiation to at least onesample, and wherein the at least one fiber arrangement includes at leastone first fiber which has at least one first filtering characteristicthat filter the electromagnetic radiation; and at least one receivingarrangement configured to receive the electromagnetic radiation that isfiltered by at least one of the at least one first fiber or at least onesecond fiber which has the at least one second filtering characteristicthat filter the at least one electromagnetic radiation.
 14. The systemaccording to claim 13, wherein the received at least one electromagneticradiation is a Raman radiation associated with the at least one sample.15. The system according to claim 13, wherein at least one portion ofthe at least one fiber arrangement is composed of or includes therein atleast one of sapphire, diamond, clear graphite, Chalcogenide,borosilicate, zirconium fluoride, silver halide, a liquid core lightguide, a gas core light guide, a hollow core waveguide, or a solid corephotonic crystal fiber.
 16. The system according to claim 13, whereinthe at least one filtering characteristic is provided by a fiber Bragggrating.
 17. The system according to claim 13, wherein at least one ofthe at least one first fiber or the at least one second fiber isfiltered based on at least one of the at least one first filteringcharacteristic or the at least one second filtering characteristic toprevent at least one portion of the at least one electromagneticradiation having particular wavelengths from being forwarded therein.18. A system, comprising: at least one first fiber arrangement includingoptical transmitting characteristics, configured to transmit therethrough at least one electromagnetic radiation and forward the at leastone electromagnetic radiation to at least one sample; and at least onesecond fiber arrangement configured to receive the electromagneticradiation that is filtered and received from the at least one sample,wherein the at least one electromagnetic radiation has at least onecharacteristic so as to at least one of reduce or substantiallyeliminate a fluorescence from the at least one sample.
 19. The systemaccording to claim 18, wherein the at least one electromagneticradiation causes a stimulated depletion of the fluorescence from the atleast one sample.
 20. The system according to claim 18, wherein the atleast one electromagnetic radiation photo-bleaches the fluorescence fromthe at least one sample. 21-41. (canceled)
 42. A method, comprising:transmitting through at least one fiber arrangement at least oneelectromagnetic radiation, the at least one fiber arrangement includingoptical transmitting characteristics; forwarding the at least oneelectromagnetic radiation to at least one sample via the at least onefiber arrangement; wherein at least one portion of the at least onefiber arrangement is composed of or includes therein at least one ofsapphire, diamond, clear graphite, Chalcogenide, borosilicate, zirconiumfluoride, silver halide, a liquid core light guide, a gas core lightguide, a hollow core waveguide, or a solid core photonic crystal fiber;and receiving the electromagnetic radiation from the at least one sampleand filtering the same using at least one receiving arrangement.